Functionalized magnetic nanochains with enhanced MR imaging: A novel nanosystem for targeting and inhibition of early glioma.

Absence of efficient targeting limits the application of magnetic nanochains (NCs) in the diagnosis of early brain cancer. Herein, dextran-coated NCs (more than 100 nm length and ∼ 10 nm cores diameter), which were modified by cyclic pentapeptide c(RGDyC) or chlorotoxin (CTX) as the targeting molecules, were fabricated via carbodiimide chemistry and thiol technique. The analysis results revealed that the obtained slender NCs exhibited good biocompatibility, superparamagnetic property, high transverse relaxivity (R2) and longer blood circulation time. The test results of human umbilical vein endothelial cells and U251 human glioma cells indicated that the conjugation of c(RGDyC) could obviously increase the cyto-internalization of c(RGDyC)-NCs, however, CTX modification could significantly enhance accumulation of CTX-NCs in U251 cells, leading to cellular apoptosis. The results of in vivo biodistribution tests and in vivo magnetic resonance (MR) imaging indicated that, although the c(RGDyC)-NCs could target early glioma to some extent and obviously enhance the contrast of MR imaging, CTX-NCs possessed higher tumor-targeting ability and good inhibition effect than the c(RGDyC)-NCs, suggesting that CTX-NCs are promising candidates for the diagnosis and therapy of early glioma.